1. Field of the Invention
The present invention relates to improvements in or relating to conveyer chains with a plurality of chain rollers, for conveying individual items or similar material handling applications. Respectively two chain rollers are coaxially arranged at a predetermined distance with respect to one another on a common chain pin in such a way so as to be able to rotate. Side bars are laterally arranged on the chain pins are used to connect respective sequentially arranged chain rollers, and the individual chain components are adapted to form an endless chain in this manner. The conveyer chain also includes conveyer rollers on chain pins, which conveyer rollers are respectively arranged between two coaxial and adjacent chain rollers. These conveyer rollers have a larger diameter than the chain rollers. Recess-like depressions which are formed between two adjacent conveyer rollers in the chain are filled by bridge-forming space members which are secured on the respective chain pins, or on sleeves.
2. Brief Description of the Prior Art
A conveyer chain of this type, also referred to as accumulating conveyer chain or accumulating roller chain, is described, for example, in German Utility Model No. 82 27 706. This type of conveyer chain is guided or supported on runner tracks or similar support members, and usually at least two endless chains are arranged in a frame at a distance and in parallel relation to one another. Such a pair of chains is synchronously driven and conveys on conveyer rollers the material to be moved. The chains are composed of a plurality of individual components, and respectively two adjacent elements form an element pair.
For conveying the material to be moved, the conveyer rollers have a larger diameter than the chain pins and the chain rollers of the chain. The chain rollers are arranged laterally and on the outside of the side bars on the chain pins in coaxial manner and are adapted to traverse on the runner track. Thus, a recess-like depression is formed between a conveyer roller, the next chain pin, or a sleeve mounted on such chain pin, and the next conveyer roller, when viewed in the direction of travel of the chain. Tramp material may fall into such recess-like depressions, and damage may be caused to the entire conveyer arrangement, as well as injuries and, consequently, disruptions of the operations can arise. For example, metallic components can fall into the recess-like depressions, causing an abrupt halt of the conveyer when these components overhang and the material to be moved collides therewith. The chain may consequently break. Furthermore, bearings may break and the entire drive arrangement may be seriously damaged. There furthermore exists the danger of accidents inasmuch that, for example, fingers of operators can inadvertently be inserted into these recesses and this may lead to considerable injuries.
It has been suggested, accordingly, in German Utility Model No. 82 27 706 to install space members or space pieces. These space pieces are placed onto the chain pin, or distance sleeve, respectively, and they cover these recesses in bridge-like manner. Such covering functions properly on straight runs. However, it has been found that lateral gaps are formed between the conveyer rollers and the space pieces at sprocket-wheel turns for the chain. Again, material can drop into such spaces, which subsequently during continued running of the chain in the straight section can also lead to damage due to the closing gaps. It is also of disadvantage in such embodiment that the space pieces of the chain can be diverted only in one direction, because the space pieces would at least nearly completely fill the distance between two conveyer rollers when the chain traverses a straight section. On traversing a turn in upward direction, the distance would be shortened which, however, is not possible due to the presence of the space pieces.